Dungeon of Mystery (1992) is one of several terrain kits put out by TSR. These are a step up from just tiles — with some folding and some glue, they create a 3D dungeon environment (Cities of Mystery, 1989, the Castles box set, 1990, and the Falcon series of Greyhawk adventures, 1990, and Strongholds, 1992, are some other similar products). I suspect that in some way most of them were some kind of reaction to the success of HeroQuest and its 3D furniture.

One of my favorite things about the Art of Dragon was the fact that it included a cardboard fold-up castle. I liked Falcon’s Revenge because of its fold-up monastery. I should probably like Dungeons of Mystery, but nope, I don’t. The fold-up components just seem so…dull. Maybe I only like fold-up cardboard things that have roofs, I dunno. Whatever the case, I am not at all tempted to fold these sheets of patterned cardstock up in the slightest.
The included booklet fares better. It goes into detail on dungeons — their purpose, their construction, how they age. I feel like this paraphrases another book, but I can’t quite remember which. It definitely downplays the idea of randomly generated dungeons, favoring plausibility. The best bit of cardboard in the box is the Dungeon Wheel assembly, which allows a dungeon, its inhabitants and traps to be generated thematically, rather than randomly. Its delightful. I love a wheel.
The booklet also has some dungeon configurations for the fold-ups. Nothing really stokes my enthusiasm as much as the wheel though.
